Electric motors are employed in a number of applications in automated production lines. For example, such motors are employed for moving a workpiece transfer slide, or for moving a drill slide to drill a hole in a fixtured workpiece. In such applications, it is necessary accurately to control both position and velocity of the motor output and load to obtain desired production goals while reducing errors and waste. Conventional error-driven servo motor drives are characterized by slow response and/or overshoot and oscillation about the final desired position. In many applications, such as drilling a hole to a desired depth in a workpiece, the ability to control overshoot and oscillation is a limiting factor on accuracy and productivity.
It is therefore the general object of the present invention to provide an electric motor servo drive which is characterized by enhanced speed and accuracy as compared with like drives of the prior art. A more specific object of the invention is to provide a servo motor drive of the described type wherein motion of the motor and load is arrested at the desired position without overshoot or oscillation.